This invention generally relates to a concentrated energy source and, more particularly, to a culminated ultraviolet light-emitting diode device for curing substances such as printer ink and adhesives.
Electromagnetic energy, particularly energy in an ultraviolet (UV) light frequency range has been found to speed curing of some substances, including fluids such as inks, coatings, and adhesives. Many of these fluids include UV photo initiators that convert monomers in the fluids into linking polymers to solidify the monomer material when the fluids are exposed to UV light. Conventional apparatus for curing substances using UV light sources include lamps and/or light-emitting diodes (LEDs) that produce light in a UV frequency range selected to optimize curing times. An LED is a type of electronic semiconductor device that emits light when an electric current passes through it.
Ink jet printers occasionally include LEDs to speed ink curing rates. Ink jet printers spray droplets of ink from a printer head onto a substrate such as film and paper. Ultraviolet LEDs direct UV light toward the ink on the substrate at a wavelength selected to speed ink curing. In the past, these LED apparatus have been inefficient in delivering sufficient energy to the ink. As a result, conventional printers having UV LED apparatus for curing ink have required LED arrays having numerous LEDs, resulting in printers of increased size, complexity and cost. Moreover, these inefficiencies have resulted in increased power usage. Conventional LED apparatus provide relatively low energy density, resulting in slow curing times. Thus, a need exists for an energy source that provides sufficient energy density to cure substances quickly. Further, there is a need for an energy source that efficiently uses energy. Still further, there is a need for an energy source that provides apparatus of smaller size, less complexity and lower cost.